This invention relates to a connection apparatus for a circuit board configured so that connector terminals come in relative slide contact with contact pads formed on a circuit board surface from a direction of a surface of the circuit board and electrically conducted thereto, and also relates to an ink jet type recording apparatus using this connection apparatus for a circuit board. The present invention further relates to an IC chip (a circuit board) having contact pads and a memory device on a base (a substrate), and to an ink cartridge having the IC chip.
For example, an inkjet type recording apparatus is configured so that a plurality of ink cartridges to be used therefor are detachably supported by a cartridge holder and that ink of each color is supplied to a recording head. Recently, there have been provided products of such a kind of a recording apparatus, which are configured so that information on the kind, color, and remaining amount of ink contained in each of the ink cartridges is held at the corresponding ink cartridge, and that the aforementioned information is transferred between a main unit of the recording apparatus and each of the ink cartridges to thereby achieve proper management of a printing operation.
Therefore, the ink cartridge has a circuit board (an IC chip) on which, for instance, a semiconductor storage device (a memory device) being capable of storing the aforementioned information is mounted. In the case that the ink cartridges are loaded in a cartridge holder, the recording apparatus employs a connection apparatus for the circuit board, which is electrically connected between the main unit and each of the ink cartridges of the recording apparatus to thereby enable the transfer of the information therebetween.
FIGS. 10A and 10B (10C) illustrate an example of a circuit board, which is used in the aforementioned recording apparatus. FIG. 10A is a plan view illustrating a state of the circuit board mounted on the ink cartridge, which is taken from above the top surface thereof. FIG. 10B (10C) is an enlarged sectional view illustrating a state of the circuit board shown in FIG. 10A, which is taken in the direction of arrows from line C—C.
A base (a substrate) 61 of the circuit board 27 is constituted by, for example, a glass epoxy resin board, on the surface of which a plurality of contact pads 62 slide-contacted with and electrically conducted to connector terminals (to be described) are formed. Further, solder resist film 63 is applied over the entire surface thereof with the exception of places, at which the contact pads 62 are formed. FIG. 10B shows a case where a minute clearance is formed between an edge of the solder resist film 63 and an edge of the contact pad 62, whereas FIG. 10C shows a case where the edge of the solder resist film 63 is overlaid on the edge of the contact pad 62.
As a result of applying this resist film 63 thereon, circuit patterns (not shown) conducted to the contact pads 62 and formed on the circuit board are coated with the resist film 63. Thus, when the circuit board 27 come in relative slide contact with a plurality of connecter terminals (to be described later), an occurrence of the electrical conduction between the circuit pattern and each of the connector terminals can be prevented. Thus, this recording apparatus prevents an occurrence of a problem that the information or data is destructed by applying an unnecessary drive voltage from the connector terminals to the circuit patterns formed on the circuit board 27 or by short-circuiting the circuit patterns through the connector terminals.
FIG. 11 illustrates a state in which the connector terminals are slide-contacted with the circuit board 27. A semiconductor storage element (a memory device) 65, for instance, EEPROM is mounted on the rear surface of the circuit board 27, and electrically connected to the contact pads 62 through the aforementioned circuit patterns and through holes (not shown). Further, the semiconductor storage element 65 is fixed to the rear surface of the circuit board 27 by a mold resin 66. The circuit board 27 is attached to an end portion of a casing formed from a synthetic resin, which constitutes an outer part of the ink cartridge, in such a way as to place the contact pads 62 on the surface thereof. This circuit board 27 is mounted in a concave portion 67 formed in the end portion of the casing to thereby perform the positioning of the circuit board 27.
Furthermore, when the ink cartridge is loaded into the cartridge holder, the circuit board 27 is adapted so that a connector terminal 70 formed from an elastic metal material placed in the cartridge holder comes in relative slide contact with the circuit board 27 from the direction of the surface of the circuit board 27 in such a way as to cause the connector terminal 70 having a curved end portion to come in contact with the pad 62 provided on the circuit board 27. That is, the circuit board 27 advances in the direction of an arrow D shown in FIG. 11. Thus, the connector terminals 70 are respectively brought into contact with the pads 62 formed on the circuit board 27 and electrically conducted thereto.
Further, a projecting part 68 projecting in the direction of the top surface of the circuit board 27 is formed at a position, at which the circuit board 27 is mounted, on the end portion of the casing. This is performed so as to prevent the end portion of the circuit board 27 from coming in contact with the connector terminals 70. That is, the base 61 of the circuit board 27 is formed like a plate from a glass epoxy resin. This material has a problem that when the connector terminals 70 directly touches the end portion, the glass material chips and thus, the circuit board 27 is damaged. Consequently, the apparatus is deliberately configured so that the end portion of the circuit board 27 does not touch the connector terminals 70.
When the connector terminal 70 is slid on the circuit board 27 and then electrically connected to the pad 62 of the circuit board 27, dust or the like, which exists on the sliding contact path, may be adhered to the connector terminal 70 and intervene between the connector terminal 70 and the pad 62.
In this case, the contact between the pad 62 and the connector terminal 70 becomes insufficient. This disables operations of reading data from and writing data to the semiconductor storage element 65 mounted on the circuit board 27. Thus, in the case of utilizing the apparatus of this configuration in managing the ink cartridges in the ink jet type recording apparatus, obstacles, such as disablement of normal printing operation of the recording apparatus, occur.
Further, in the case where the projecting portion is formed on the circuit board mounting portion at the end of the circuit board, the connector terminals 70 override the projecting part 68 and then come in contact with the surface of the circuit board 27. Since the circuit board 27 advances in the direction of the arrow D. the end portions of the connector terminals 70 are brought into contact with the surfaces of the pads 62 formed on the circuit board 72. Therefore, when the connector terminal 70 overrides the projecting part 68, the surface of the projecting part 68 formed from, for instance, a synthetic resin is subject to friction caused by the connector terminal 70, and thus undergoes an action by which the material is worn.
Also, in this case, the resin material becomes floury dust and adheres to the connector terminal 70. Then, such dust intervenes between the pad 62 and the connector terminal 70.